decker



F. J. DECKER.

PORTABLE onmome MACHINE.

Patented Sept. 23, 1919.

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F. J. DECKER.

' PORTABLE GRINDING MACHINE.

APPLICATION FlLE D MAR. I3. 1918.

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F. J. DECKER.

PORTABLE cmnoms MACHINE.

' APPLICATION FILED MAR. I3, I918. 1,316,942.. Patented Sept. 23, 1919.

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{a BY; rF/Z f9 66 ATTORNEY 6a as I 7 UNITED STATES PATENT OFFICE.

FREDERICK J. DECKER, OF ROCHESTER, NEW YORK, ASSIGNOR TO SHAFER-DECKER00., INC, OF ROCHESTER, NEW YORK, A CORPORATION.

PORTABLE GRINDING-MACHINE.

Specification of Letters Patent.

Patented Sept. 23, 1919.

Application filed March 13, 1918. Serial No. 222,097.

To all whom it may concern:

Be it known that I, FREDERICK J. DECKER, a citizen of the United States,residing at Rochester, in the county of Monroe and State of New York,have invented a new and Improved Portable Grinding-Machine, of

which the following is a specification.

This invention while relating to grinding machines in general has moreespecial reference to those of the portable type and is particularlyadaptable for use in grinding commutators of dynamo-electric machines.

One of the objects of my present invention is to provide aportable'means for truing or resurfacing revolving cylindrical bodiessuch, for instance, as commutators without having to remove them fromthe machines of which they form a part as doing so, especially inremoving the commutators of large dynamo-electric machines, involvesconsiderable time, labor and expense.

It is necessary that commutators be resur faced from time to time topreserve cylinvdricity because, in action, they are subject to unevenwear from friction of the brushes and the burning action of destructivesparks; and it is a further object of my invention to make use of agrinding wheel as the resurfacing means and to support the wheel in suchmanner that the operation may be performed while the commutator isrevolving at normal or even greaterthan normal speed, thus assuring moreperfect cylindricity.

Another object of the invention is to construct the machine withsuchfeatures of adju'stment that it can be placed in approximatelyoperative position and then readily adjusted in a manner to bring theaxis of rotation of the grinding wheel parallel with that of thecommutator and at a proper height relatively thereto.

Another object ofthe invention is to provide a lateral feed for thegrinding wheel of such a nature that an extremely fine adjustment can bemade and a very fine cut taken off the surface of the commutator.

,These and other objects of the invention pertaining more to details ofconstruction will be more clearly brought out in the followingdescription and particularly defined in the appended claims.

While I have referred to my invention as particularly adaptable forgrinding commutators and will throughout the specification speak of itas used for such purpose, it will, of course, be readily understood thata mach1ne constructed in accordance therewith may as effectively be usedfor grinding other revolving cylindrical bodies so supported that thegrinding wheel can engage and traverse their surface.

The accompanying drawings illustrating a machine constructed inaccordance with my invention are as follows Figure 1 is a plan view ofthe machine with parts broken away to more clearly show details ofconstruction.

Fig. 2 is a side elevation of the machine with parts broken away to moreclearly show details ofconstruction and with the motor removed.

Fig. 3 is a longitudinal sectional detail taken on the line 3-3 of Fig.1.

Fig. 4.- is a transverse sectional view of the base taken on the line4:4: of Fig. 2.

Fig. 5 is a plan view ofthe right hand end portion of the base withrespect to Fig. 2.

Fig. 6 is a vertical sectional View taken on the line 66 of Fig. 1;

Fig. 7 is a sectional View taken on the line 7-7 of Fig. 8. a

Fig. 8 is a sectional view taken on the line S8 of Fig. 2. I

Fig. 9 is a vertical sectional detail on the line 9-9 of Fig. 1 showingthe manner of adjustably supporting the motor upon the bracket therefor.

Similar reference numerals refer to similar parts throughout thedrawings.

The numeral 1 represents the base which is of rectangular conformationand comprisesright and left hand transverse covered portions 2 and 3,respectively, connected by side walls 4. having reinforcing ribs 5 andinwardly extending flanges 6 along their lower edges.

Supported upon the base portion 3 and pivotally connected thereto by acentrally disposed vertically extending bolt 7 is a swivel head 8, suchbolt being provided on its upper end with a nut 9 which, when loosened,permits an angular adjustment of the head. This head 8 is formed with apair of oppositely positioned upright arms 10 having split bearings attheir upper ends, provided with clamping bolts 11, and in which bearingsare supported the ends of a bolt or shaft 12. Revoluble on the bolt 12and engaging between the arms 10, 10

to prevent endwise movement is an extension member 13 formed integrallywith a [tube supporting head 14 having a boreat "right angles to thatofthe extension memher.

in the manner shown and provided with clamping bolts 16 whereby it isnormally held against rotation. It will thus be seen This extensionmember is slotted at that the tube head 14 may be angularly adjustedabout both a vertical and a longitudinal axis. i

Movably supported upon the right hand transverse base portion 2 is astandard 17 having arms 18extending upwardfrom its ends, such armshaving slots 19 therethrough each forming an arc ofa circle having aradius extending fromthe axial center of the bolt 12 and these arms arerecessed on their outer faces to receive the heads 20 and nuts 21 oftie-bolts 22 engaging through laterally extending bosses 23 formed onthe right hand tube supporting head 24. 7

Supported in the heads 14 and 24" and extending slightly beyond theouter ends thereof is a tube'25 which; is held against longitudinalmovement 'by rightand left/hand cap members 26 and 27, respectively, se-

cured to the tube by screws'28 and having their inner ends engaging. the'outer'ends' of their respective head members. The head 24 is slottedalong the top and the head 14 along one side, in'the manner shown, andthe tube is normally held against rotation' bythe upper tie-bolt 22 forthe head 24 and a clamping 'bo1t 29 for the head 14-which engagesthrough the upper and is threaded in the lower ,one of bosses [3O 7formed thereon. Thetie-bolts' 22 are keyed to the tube head 24 at. 31 toprevent their rotation. "L'ooseningth'e nuts 21 on the tie-I bolts 22and-the clamping bolts 16 hereinbefore described permits an angularraising or lowering in a vertical plane of theitube 25 45 which isafi'ected'in the following manner The tube head "24 rests upon the head32 of a vertically extending bolt 33 threaded in the upper end of atubular member 34, such member extending through. a projection 35 in thecenter of the base portionof the standard 17 and being held in itsproper position of vertical adjustment by a nut 36 threaded thereon. Thebolt 33 is'rais'ed' or. lowered by turning with a' suitable wrench andas it is rals'ed 1t carries 'with'it the head'24 and tube 25 and as itis lowered these members drop by gravity. 7

The tubular member 34 engages through the side walls of the right handbase portion I 2 and is held against endwise movement its head 42 andnut 43. Itwill thus be seen i that b y'turning the screw 39 the trunnionnut may be movedeither to the rightor left as desired and that such nutby its engage- The cap members 26and 27 are formed;

'7 with inwardly extending central portions forming bearings for afeedscrew44 wlthin thetube 25 and which is held, against end play by a nut.45 on the left'and the'hub'o'f a hand-wheelj46 keyed to the right handends thereof, such nut 45 and hand wheel 46 having suitable washersdisposedb'etween them and their respective cap members. if Threaded onthe said feed screw 44 isia' nut 47 having a spline 48 engaging in a 3channel 49 formed in the" top of the tube 25' and extending between theinner ends of the it tube heads 14 and 24. This'spline engages in arecess formed-in anoflset portion 50'o'f i a sleeve '51 slidable on thesupporting tube '25 and is secured-to such sleeve by screws52;

while to permit the sleeve to move freely on the supporting tube thesleeve is slotted lon gitudinally alonglone' side, in the manner shown,and provided with lugs 53 for re-' ceiving the clamping bolts 54'whichare' ad justed to securea proper fitting ofthe' parts.

Formed integrallywith the sleeve 51 is5a motor supporting bracket 55extendingout- Wardly therefrom,- or toward the observer 'with respect toFig. l,- and reinforced by webs 56.

adjustment back or forth on the bracket, for

the purpose hereinafterdescribed,by: the

Supported upon-:this'bracket 55is a mo tor 57 the feet 58 of which restupon the studs 60 provided with clamping nuts 61} and'62' and'sprin'gwashers "6-3 engaging be -i;

tween "the nuts'62 and'the under side of the bracket. I grooved toreceive longitudinally extending The bottoms of the feet 58are' andparallel guiding bars 64 slidable" with the motor when the same is beingadjusted and engagingfin channels 65 therefor in the V raised corners 59of-the bracket and these raised corners are also slotted at 66 to rebolted a plate '67 comprising a nut into.

screw between the bracket extension 69=and aretaining nut .70 is anoperating crank 71 provided with ahandle '72. Turning this 7 1-20 ceive'and permit movement of themotor studs. Toflthe front" of the motor"there is;

crank will eficct an adjustment backor forth as desired of the motor onits support for. the purpose of tightening the belt 7 3-, as will beexplained. While the nuts 61 and 62 on the motor studs 60 will be turnedsufficiently tight to hold the motor against any accidental movementback or forth due to vibration during the operation of the ma chine, themotor is not clamped to the bracket, due to the action of the springwashers 63, so rigidly but what it can be adju-sted by means of it feedscrew 68 with out the necessity of adjusting thenuts on the studs eachtime such motor adjustment is re -uired. v

lso formed integrally with the sleeve 51 and extending paralleltherewith but on the side opposite the motor bracket 55 is a tubular arm74 connected to the sleeve by a pair of outwardly extending verticalribs or arms 75 and a centrally disposed longitudinal extending web 76'.The ends of this tube 74 comprise bearings for a spindle tube 77 mountedtherein and secured within this spindle tube at its right and left handends by screws 78, with reference to Fig. 1, are eccentric 79 and 80,respectively, while threaded within these eccentrics are tapered thrustbushings 81 forming bearings for a spindle shaft 82. The tubular arm 74is slotted at each end but on reverse sides and for a distanceapproximately the length of the eccentrics 79 and and is provided aboveand below such slots with lugs 83 for receiving clamping bolts 84, thesebolts being adjusted to permit rotation of the spindle tube 77 but nottoo freely.

The right hand end of the tube 77 extends slightly beyond its supportingarm 74 and has fixed thereon a worm Wheel 85 'which meshes with a worm8'6 fixed to a shaft revolu-bly supported in bearings formed on abracket 87 secured to the right hand connecting arm 75 and having fixedthereto above uch bracket the shank 88 of a suitable operating handle89. Threaded on the right hand end of the shaft 82 are a pair of thrustbearing adjusting nuts 90 between which and their respective thrustbearin 8-1 are a pair of metal collars 9-1 with a 'ber collar 92 betweenthem; and keyed to the outer end of the shaft is a pulley 93 alined witha pulley 94 fixed to the motor shaft 95. Keyed to the reduced portion ofthe shaft 82 at its opposite end is a coupling flange 96 between whichand the head of its respective thrust bearing 81 is a fiber collar 97and a steel collar-98, whilefixed to the shaft at the end of thiscoupling flange is the hub 99 on which is secured the grinding wheel100. Nuts 101 threaded on the ends of the shaft hold the wheel 100 andpulley 93 in place. The grinding wheel may be of any preferred typeaccording to the work to be done but when the machine is used forgrinding commutatorsa wheel especially made for this purpose is used.

As the nut 47 is moved in one direction or the other on the feed screw44 by turning the hand wheel 46 it carrieswith it the sleeve 51 andparts supported thereby, viz.,the motorbracket 55 and tubular arm 74with their respective members. In this manner the grinding wheel iscaused to traverse the face of the commutator, or other object beingground, and to limit the distance of such,travel, split stop rings 102encircle the supporting tube 25, one each side ofthe sleeve 51,. and areadapted to be clamped to the tube in any desired position oflongitudinaladjustment by the bolts 103 carried thereby.

'From the description it will be noticed that the wheel shaft 82 iseccentrically suported and that by rotating the eccentrics 9 and 80through the medium of the tube 82, worm wheel 85, worm 86 and operatinghandle 89, a lateral movement of the grinding wheel 1 00 in onedirection or the other is effected. This lateral feed of the grindingwheel, it will of course be understood, is to bring the wheel intocontact with the surface of the object to be ground and the eccentricmovement permits of an extremely fine feed adjustment. The shaft. 82 isdriven from the motor shaft by means of the belt 73 engaging over theirrespective pulleys 98 and 94,. and this belt is tightened by theadjustment back or forth of the motor 57, in the manner hereinbeforedescribed, such adjustment being necessitated by the lateral movement ofthe shaft 82. The grinding wheel travels in the reverse direction tothat of the object being ground.

The spline 48 prevents rotation of the sleeve 51 on the supporting tube25, but should it be desired in the adjustment of the machine to raiseor lower the axis of rotation of the grinding wheel relatively to thatof the object being ground the same may be accomplished by loosening theclamping bolts of the tube heads 14 and 24 and giving the supportingtube 25 the required amount of rotation which can be done by theoperator lifting or lowering, as required, either themotor bracket 55 orthe tubular arm 74. When this adjustment has beenmade the aforesaidclamping bolts are again tightened.

When the machine is used for grinding commutators it is set up in thefollowing manner It should first be understood that only enough of theframe work supporting the commutator and the commutator brushesthemselves need be removed that will permit the grinding wheelbeingbrought into engagement with the periphery of the commutator across itsentire surface. The machine is securcd to a heavy plank indicated at 104in Figsa2I and 4, by means of base clampingplates 105 which .eXtendbetween the side walls-4 of the' base and engage the flanges 6, each ofsuch plates having a centralve'rtical projection 106 bored out toreceive a bolt 107 which nlso extendsjthroughi a hole infthe plank andhas a clamping nut, not shown, threaded on its lowerend. The plank 104is then supported uponbloeks so that the machine will be approximatelyin the desired position, after which the several adjustments ofthemachine are'made as follows:' 1 vf 7 First, true horizontal positionfor the supporting tube 25 is'secured by raising or lowering the samebyturning the vertical adjusting bolt 33 in the manner described and 1after which the-nuts 21 on the bolts 22 of the-supporting head 24 andthe: bolts 16' cf-the 'hea'd14 are tightened; and, to'

be able to readily determinewhen' thersup porting tube is level, aspiritlevel 108 is provided on the sleeve 51' orin any other suitableposition. The tubular 1 arm 74, it

'will be "understood, is' always parallelwith the supporting tube 25 sothat iwhenone' is in horizontal "position lthe "other 'is :also..

5 Then, if a'lateral'adjustment is'necessary in order to bringthe-face'of the grinding wheel malspeed. I have found it'necessary,also, a

when grinding commutators, that the cut,

10.0 1parallel with that of the commutator,

indicated at-109 in Fig.v 1, the screw-39 is operated which effects anangular rotation of the supporting tube 25 and parts carrled thereby onthe bolt 7 *as an axis, and-when this adjustment hasz beenmade the nuton the pivot bolt is tightened to prevent further lateral movement.Should it be desiredto adjust the relative position,higher or lower, ofthe grinding wheel and commutator this may be accomplished by raising orlowering the tubular arm 74 which caused a partial rotation of thesupporting tube '25 in the heads 14 and 24, after which the clampingboltsfor such heads are tightened to secure this adjustment. V

be regulated accordingwto. the, current of thejmotor' for: driving the.grinding wheel,

and for this reason an ammeter connected in series with the motor isplaced in such position that it can at all times be read by the operatorof the machine.

' The machine may be used for grinding,

burnishing or other like; purposes and the kind of wheeloloolthat isusedWill be atermined accordingly,'one of speciallcom position forgrinding'copper being employed when the machine isused on commutators;

but as the machineisprimarily a grinder I will referto the elementhl00,in: the claims,-

as a=grinding Wheel although not necessa- ,rily limitingtheinvention tothejuse of such.

@It is believed thatfromtheforegoing deg scription'the purpose,construction and mannerof operating the grinding machine are for nofurther ex sufiiciently clear to call planation herein. What I claim isa a 1. In a machine of'the character described,

a support, a member slidable on said support,bearings anda motor bracketboth car,- riedby said slidable member, a' shaft revolubly supported insaid bearings, a grinding wheel fixed to said shaft, a motor supportedshafthv- Y Y on said,bracket,iand connections between said motor andsaidshaftfor driving the 2., In a'machine ofthe character described, 7

a support, a memberslidablelon said; support,-bearings and amotorbracket carried by said slidable member on oppo'site sides of saidsupport, a' shaft revolubly supported in saidbearings,-'a grinding wheelfixed to said shaft, a motor supported on said, bracket,

and connections between said motor; andsaid shaft for drivingthefshaft.

3;. {In a machine of the character described, asupport, a; memberslidable on said support, bearings and. a motor bracket carried by saidslidable member on-opposite sides 7 of said support, a laterallyadjustable shaft 'revolubly supported in said bearings, a grindin wheelfixed to said shaft, a motor adjusta ly' supported on said bracketyandconnections between said motor. andfsaid shaft for driving the shaft.

4. Ina machine of thecharacter described, V

a support pivotally mounted to be swung' in both a vertical and ahorizontal plane, a

member longitudinally slidable on said support and having-arr angularadjustment in a plane atv right angles to such longitudinal movement,'anadjustably supported motor *and bearings both carried-by said slidablemember, a laterally adjustable shaft revo" lubly supported insaid;bearings, agrinding V wheel-fixed to said shaft, and connections betweensaid 'motor' and, said shaft for' driv- :ing th6'Sh2tft;. 5.- In amachine ofthe character described,

a supporting tube, a sleeve slidablelon said tube, a tubular armand-amotorfbracketfcarried'by. the sleeve onop'p'osite sides of said .tubefajshaft revolu'bly supported in said arms, a grinding wheel fixed to saidshaft, 7

a motor supported on the saidbracketjand V tor foridriving the shaft, t6 In a machine ofthe character described,

connections between said shaft and said mo- I a supporting tube, asleeve slidable on said tube, a tubular arm and a motor bracket carriedby the sleeve on opposite sides of said tube, a shaft revolublysupported in said tube, means for laterally moving said shaft, a grindinwheel fixed to said shaft, a motor adjustzfifly supported on the saidbracket, and'connections between said shaft and said motor for drivingthe shaft.

7. In a machine of the character described, a supporting tube, a sleeveslidable on said tube, a tubular arm and a motor bracket carried by thesleeve on opposite sides of said tube, eccentrics revoluble in said arm,a shaft revolubly supported in said eccentries, means connecting saideccentrics to cause like rotation thereof, means for rotating saideccentrics to effect a lateral movement of the shaft, a grinding Wheelfixed to one end of said shaft, a motor adjustably supported upon saidbracket, and connections between the opposite end of said shaft and saidmotor for driving the shaft.

8. In a machine of the character described, a base, a swivel headsupported on the base and having a vertical axis of rotation, arms onsaid head, a horizontally disposed shaft supported in said arms andmeans for normally securing the same against rotation, a memberrotatably mounted on said shaft, a supporting head formed on said memberand having a bore at right angles to said shaft, a tube supported by androtatable in said head, and means as clamping bolts, for normallyholding the said rotatable members in their respective positions ofangular adjustment.

9. In a machine of the character described, a base, a tubular memberpivotally supported at one end abovesaid base so that its position maybe ad usted angularly 1n a vertical plane, base, and a supporting headfor the other end of said tubular member slidably sup ported in saidstandard.

10. In a machine of the character described, a base, a tubular memberpivotally supported at one end above sald base so that its position maybe adjusted angularly in both a vertical and a horizontal plane, astandard laterally adjustable on said base, and a supporting head forthe other end of said tubular member slidably supported in saidstandard.

11. In a machine of the character described, a base, a tubular memberpivotally supported at one end above said base so that its position maybe ad usted angularly in both a vertical and a horizontal plane, astandard laterally adjustable on said base, such standard comprising abase portion and a pair of upwardly extending slotted arms, a supportinghead for the opposite end of said tubular member engaging between thesaid arms, and means, as bolts extending a standard supported on saidthrough the supporting head for adjustably securing the same to saidarms.

12. In a machine of the character described, a base, a standardsupported on the base, a member vertically slidable in said standard, avertical adjusting screw threaded into said standard and having one endengaging the said member, and means for securing the said member to thestandard.

13. In a machine of the character described, a base having a guidingslot therein, a lateral feed screw supported in said base, a standardlaterally adjustable on said base, a trunnion nut on said feed screw, ahead straddling said feed screw and slotted to receive the trunnions onsaid nut, and an extension from said head engaging through the said slotand secured to said standard, all for the purpose set forth.

14. In a machine of the character described, a base having a guidingslot therein, a lateral feed screw supported in said base, a standardlaterally adjustable on said base, a trunnion nut on said feed screw, ahead straddling said feed screw and slotted to receive the trunnions onsaid nut, a tubular extension on said head engaging through the saidslot and secured-to said standard, and a vertical adjusting screwthreaded into said tubular extension, all for the purpose set forth.

15. The combination, in a machine of the character described, of a base,a supporting tube having a longitudinally extending slot, members onsaid base for supporting the said tube, a longitudinal feed screwsupported Within saicLtube and means for operating the same, a sleeveslidable on said tube, a tubular arm and a motor bracket formed on saidsleeve on opposite sides of the tube, a spline engaging in the said slotand secured to said sleeve, a nut on said feed screw formed integrallywith said spline, a shaft revolubly supported in said tubular arm, meansfor laterally adjusting the shaft, a 110 motor adjustably supported onsaid bracket, a grinding wheel fixed to one end of said shaft, andconnections between the other end of said shaft and said motor fordriving the shaft.

16. The combination, in a machine of the character described, of a base,a supporting tube having a longitudinally extending slot, members onsaid base for supporting the said tube, a longitudinal feed screw sup-12 ported within said tube and eans for operating the same, a sleeveslidable on said tube, a tubular arm and a motor bracket formed on saidsleeve on opposite sides of the tube, a spline engaging in the said slot125 and secured to said sleeve, a nut on said feed screw formedintegrally with said spline, a shaft revolubly supported in said tubulararm, means for laterally adjusting the shaft,

a motor adjustably supported on said 130 bracket,- a grinding wheelfixed to one end of said shaft, connections between the other end ofsaid shaft and said motor for driving the shaft, and stop ringsadjustable on said supporting tubefor limiting the movement of saidsleeve.

'17. The combination, in a machine of the character described, of abase, a supporting tube having a longitudinally extending slot, memberson'saidbase for supporting the said tube, a longitudinal feed screwsup-1 ported Within said tube and means for operating the same, asleeve-sli'dable on said tube,'a tubular arm' and a motor bracket formedon said sleeve on opposite sides of the tube, a spline engagingin thesaid slot and secured to said sleeve, a nut on said feed screw formedintegrally with said spline, a tube revolubly supported in said tubulararm, eccentrics secured'within said a Second named tube, ashaftrevolubly supported in said eccentrics, a worm wheel on the saidsecondnamedtube, a worm in mesh with said wheel, bearings on saidtubular arm for said worm, means for operating the said worm to effectthroughthe rotation of said eccentrics a lateral adjustment of said 7shaft, a motor adjustab-ly supported on said bracket, a grinding wheelfixed to one end of sa1d shaft, and connections between the other end ofsaid shaft and said motor for said tube, a tubulararm and a motorbracket formed on said sleeve on opposite sides of the tube, a'splineengaging in the said slot and secured to said sleeve, a nut on said feed7 screw formed integrally with said spline, a shaft revolubly supportedin said tubular arm, means for laterally adjusting the shaft, a motoradjustably supported on said bracket, a grinding wheel fixed to one'endof said shaft, and connections between the other end of said shaft andsaid motor for driving the shaft.

19. The combination, in a machine of the character described, of a base,a supporting tube having a longitudinally extending slot,

such tube being supported above said base in a manner that its positionmay be adjusted angularly in a horizontal plane and means for effectingsaid adjustment; members on said base for 'rotatably supporting saidtube and means for normally securing 1t against rotation; alongitudinalfeed'screw supported within said tube and means foroperating the-same,a sleeve slidable on said tube, a tubular arm andamotor bracket, formed on said sleeve on opposite sides of the tube, aspline engaging in the said slot and secured tosaid' sleeve, a; nut onsaid feed screw formed integrally with said spline, a shaft revolublysupported in said tubulararm, means for"-laterally adjusting the shaft,a motor adjustably supported on said bracket, a grinding wheel fixed toone end'ofsaid shaft, and connections between the other end of saidshaft for driving the shaft e 20. The combination; in a machine of thecharacter described, of a base, a supporting tube having alongitudinally extending slot,

such tube being supported above said base in amanner that its positionmay be adjusted angularly in both avertical and a horizontal plane andmeans for .effectlng each of said and said motor 7 adjustments; memberson saidbase for rov t-atably'supporting said tube and means for normallysecuring it against; rotation; a longitudinal feed screw supportedwithin said tube and means for operating the same, a sleeve slidable onsaid tube, atubular arm and a motor bracket formed on said sleeve onopposite sides of the tube, a spline engaging in the said slot'andsecuredto said sleeve, a nut on said feed screw formed integrally ,withsaid spline, a shaft revolubly supported in said tubular arm, means forlaterally adjusting the shaft, a motor ad justably supported on saidbracket, a grinding wheel fixed to one end of said shaft, andconnections between the other end of said shaft and said motor fordriving the shaft.

21. The combination, in a machine for grinding commutators, of a base, asupporting tube having alongitudinally extending slot, members on saidbase'for supporting the said tube, a longitudinal feed screwsupportedwithin said'tube and means for op; eratingthe same, a sleeveslidable on said tube, a tubular arm and a motor bracket formed; on saidsleeve onopposite sides of the-tube, a spline engagingin the said slotand secured to said sleeve, a nut on said feed screw formed integrallywith said spline, a v V shaft revolubly supported in said tubular arm,means for laterally adjusting the shaft, a motor adjustably supported"on said bracket,a grinding wheel fixed to one end of said shaft, andconnections between the other end of said shaft and said motor fordriving the shaft, the said grinding wheel being adapted to travel in areverse direction' from that 'of the commutator and to permit the latterto revolve at is normal or greater than normal speed; 22. A grlndingmachlne comprising a base, a guide, a connection between the base andthe guide permitting the latter to swing about two axes at right anglesto each other and to the guide, a carriage movable on the guide, amember mounted to turn on the carriage about an axis parallel with theguide, and a grinder eccentrically carried by said member so that theturning of the member effects the feeding of the grinder.

23. A grinding machine comprising a base, a guide, a carriage movablealong the guide, a member mounted to turn on said carriage about theaxis parallel with the guide, and a grinder eccentrically carried bysaid member so that the turning of the member effects the feeding of thegrinder.

24. A grinding machine comprising a base, a guide, a connection betweenthe base and the guide permitting the guide to turn about two axes atright angles to each other and to the guide, a carriage movable alongthe guide, a tubular member rotatable on the carriage about an axisparallel with the guide, a shaft extending through the tubular memberand arranged eccentrically with reference to said member, and a grindercarried by said shaft.

25. A grinding machine comprising a base member, a guide, a connectionbetween the guide and the base member permitting the guide to swingabout two axes at right angles to each other and to the guide, acarriage adapted to move on the guide, a member mounted to rotate on thecarriage about an axis parallel with the guide, a grinder carried bysaid rotary member mounted to turn about an axis eccentrically to andparallel with said rotary member so that the turning of the rotarymember effects the feeding of the grinder, a mechanism for turning saidrotary member comprising a worm wheel on the rotary member, and a wormcooperating with said worm wheel and acting to lock the rotary member inits adjusted position.

FREDERICK J. DECKER.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, I). C.

